化学学报 ›› 2014, Vol. 72 ›› Issue (2): 241-245.DOI: 10.6023/A13101057 上一篇    下一篇

研究论文

基于离子液体修饰介孔硅的免标记电化学免疫测定双组分肿瘤标志物

林洁华, 张慧慧, 邵美佳   

  1. 青岛科技大学化学与分子工程学院 青岛 266042
  • 收稿日期:2013-10-14 出版日期:2014-02-14 发布日期:2013-12-12
  • 通讯作者: 林洁华,E-mail:linjiehua@qust.edu.cn E-mail:linjiehua@qust.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos. 20905041,21075073)和山东省博士基金(No. BS2011SW008)资助.

A Label-free Immunosensor based on Ionic Liquids Modified Mesoporous Silica for Simultaneous Determination of Two Tumor Markers

Lin Jiehua, Zhang Huihui, Shao Meijia   

  1. College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042
  • Received:2013-10-14 Online:2014-02-14 Published:2013-12-12
  • Supported by:

    Project supported by the Natural Science Foundation of China (Nos. 20905041 and 21075073) and the Doctoral Foundation of Shandong Province (No. BS2011SW008).

建立了一种可同时检测双组分肿瘤标志物的免标记电化学免疫测定方法,检测了人血清样品中癌胚抗原(CEA)和甲胎蛋白(AFP)的含量. 在实验中,我们首先将二种电化学底物,二茂铁甲酸(FCA)和亚甲基蓝(MB),分别结合在离子液体(IL)修饰的介孔硅(MPS)的孔道内,制备FCA-IL-MPS和MB-IL-MPS复合材料;然后将免疫探针涂覆在掺铟氧化锡(ITO)电极表面的不同部分;最后将CEA单克隆抗体(anti-CEA)和AFP单克隆抗体(anti-AFP)分别负载到两种材料的孔内,制得CEA和AFP的免标记免疫探针(anti-CEA/FCA-IL-MPS,anti-AFP/MB-IL-MPS),组装得到双组分的免标记免疫传感器. 当该免疫传感器在含有抗原的样液中温育后,CEA和AFP抗原通过特异性免疫反应而结合到MPS孔道内. 由于形成的免疫复合物不导电且有一定的空间位阻,所以对电极表面的电子转移产生了阻碍. 根据ITO不同位置上响应电流的变化实现对CEA和AFP含量的同时测定. 本方法对CEA和AFP的检测线性范围分别为0.5~80 ng·mL-1和0.5~100 ng·mL-1,检测限分别为0.1 ng·mL-1和0.1 ng·mL-1S/N=3). 离子液体具有高导电率,能实现所构建体系信号的放大,使制备的免疫传感器具有良好的灵敏度.

关键词: 免疫传感器, 双组分, 介孔二氧化硅, 免标记测定, 肿瘤标志物

A label-free electrochemical immunoassay strategy was proposed for the simultaneous detection of two tumor markers, carcinoembryonic antigen (CEA) and α-fetoprotein (AFP). The functional mesoporous silica was synthesized for the construction of the label-free immunosensor. The Si-OH groups on the external surface of the mesoporous silica were terminated by trimethylchlorosilane (TMCS), while the Si-OH groups on the internal pore walls were modified with amino groups. The electrochemical substrates of ferrocenecarboxylic acid (FCA) and methylene blue (MB) were co-immobilized inside the channels of the ionic liquids (ILs) modified mesoporous silica (MPS), respectively. The monoclonal antibody of CEA (anti-CEA) and the monoclonal antibody of AFP (anti-AFP) were respectively co-immobilized inside the materials of FCA-IL-MPS and MB-IL-MPS. The ITO slide was separated lengthways into two uniform parts by insulation glue so as to avoid the cross-talk of the two portions. Finally, the suspension solutions were coated respectively onto the different areas of indium-tin oxide (ITO) electrode. The double-analyte immunosensor was constructed by the probes of CEA and AFP onto the different areas of ITO. When the double-analyte immunosensor was dipped into the sample solution, the antigens of CEA and AFP reacted with their corresponding monoclonal antibodies on the different area of the modified ITO electrode. After the immunological reaction, the nonconductive immunoconjugates formed inside the MPS channels. With the increasing concentrations of CEA and AFP antigens, the spatial blocking and impedance on the sensor surface increased, thus the electric response transfer from the solution to the electrode surface was blocked and the DPV currents decreased. The electrochemical signals for CEA were detected by using FCA as the electron mediator. The electrochemical signals for AFP were detected by using MB as the electrochemical substrates. Then, the simultaneous detection of CEA and AFP could be achieved. The electrode modification process was further characterized by cyclic voltammetric measurements and electrochemical impedance spectroscopy. IL units inside the mesopores could promote the electron transportation through the pore channel. To clarify the adsorption of FCA and MB into the mesopores of ILs-modified MPS, the IR spectra were recorded. The linear ranges of CEA and AFP were 0.5~80 ng·mL-1 and 0.5~100 ng·mL-1 with the detection limits of 0.1 ng·mL-1 and 0.1 ng·mL-1 (S/N=3), respectively. The fabricated immunosensor shows appropriate sensitivity because of the good electric conductivity of ILs. It is an alternative to the multianalyte detection of antigens or other bioactive molecules.

Key words: immunosensor, double-analyte detection, mesoporous silica, label-free determination, tumor markers